[morzh]

Fran

I have rebuilt several Philco radios that use this or very similar type of Tone control, including 90 and 70 models.
This is the first time I hear about this defect having occurred. The effort of the sliding contact moving across the contacts' caps is very light.

Well, in the worst case for a while you will have to operate the radio without the tone control, it will just work at the peak of the treble transfer; when you locate the new control or fix this, you could install it.